504 research outputs found
Development of a standardized social service pathway for children with complex cerebral palsy: The social production of disability
From a cultural-historical perspective, the impairments of a child with a condition like cerebral palsy (CP) have biological origins, but the disability evolves from the mismatch between the child and his/her social conditions for development (Vygotsky, 1993). One example of this dialectical production of disability can be seen in the challenge of the 21st-century welfare state: How to provide economically feasible health and educational services anchored in evidence-based methods and practices. Standardized social service pathways for children with CP illustrates an attempt to address this challenge and moderate the mismatch by acting in the intersection between impairment and society. The aim of the article is to analyze challenges in the practice of connecting research and practice-based knowledge with societal practices in order to diminish the disability of the child. A multidisciplinary group assembled by the Danish National Board of Social Services engaged in a practice of developing a guideline for a social service pathway. Agendas and minutes from their series of meetings provide insight in how the work evolved through conflictual discussions. Rather than a neutral transformation of knowledge into practice, the practice revealed itself as a value-laden process in which the needs of the child and family were at times decentred and the focus shifted to how social services could be realised in complex, structured social practices. While the group managed to overcome several conflicts and agree of a social service pathway, a socio-economic analysis was unable to argue for the comprehensive social service pathway as an economic sound choice for municipal decision-makers. The conflict between the welfare ideology and economic feasibility remains unresolved and can be expected to limit the extent that impairments can be remedied and the mismatch decreased. Overcoming or diminishing the mismatch might never become economic worthwhile. As the political pendulum oscillates between welfare and economic concerns, the experience of disability will likewise diminish or expand
Tracing Outflowing Metals in Simulations of Dwarf and Spiral Galaxies
We analyze the metal accumulation in dwarf and spiral galaxies by following
the history of metal enrichment and outflows in a suite of twenty
high-resolution simulated galaxies. These simulations agree with the observed
stellar and gas-phase mass-metallicity relation, an agreement that relies on
large fractions of the produced metals escaping into the CGM. For instance, in
galaxies with Mvir ~ 1e9.5 -- 1e10 solar masses, we find that about ~ 85% of
the available metals are outside of the galactic disk at z = 0, although the
fraction decreases to a little less than half in Milky Way-mass galaxies. In
many cases, these metals are spread far beyond the virial radius. We analyze
the metal deficit within the ISM and stars in the context of previous work
tracking the inflow and outflow of baryons. Outflows are prevalent across the
entire mass range, as is reaccretion. We find that between 40 and 80% of all
metals removed from the galactic disk are later reaccreted. The outflows
themselves are metal enriched relative to the ISM by a factor of 0.2 dex
because of the correspondence between sites of metal enrichment and outflows.
As a result, the metal mass loading factor scales as eta_metals \propto
v_circ^-0.91, a somewhat shallower scaling than the total mass loading factor.
We analyze the simulated galaxies within the context of analytic chemical
evolution models by determining their net metal expulsion efficiencies, which
encapsulate the rates of metal loss and reaccretion. We discuss these results
in light of the inflow and outflow properties necessary for reproducing the
mass-metallicity relation.Comment: Under review by ApJ. 21 pages, 15 figure
High Velocity Dispersion in A Rare Grand Design Spiral Galaxy at Redshift z=2.18
Although relatively common in the local Universe, only one grand-design
spiral galaxy has been spectroscopically confirmed to lie at z>2 (HDFX 28;
z=2.011), and may prove to be a major merger that simply resembles a spiral in
projection. The rarity of spirals has been explained as a result of disks being
dynamically 'hot' at z>2 which may instead favor the formation of
commonly-observed clumpy structures. Alternatively, current instrumentation may
simply not be sensitive enough to detect spiral structures comparable to those
in the modern Universe. At redshifts <2, the velocity dispersion of disks
decreases, and spiral galaxies are more numerous by z~1. Here we report
observations of the grand design spiral galaxy Q2343-BX442 at z=2.18.
Spectroscopy of ionized gas shows that the disk is dynamically hot, implying an
uncertain origin for the spiral structure. The kinematics of the galaxy are
consistent with a thick disk undergoing a minor merger, which can drive the
formation of short-lived spiral structure. A duty cycle of < 100 Myr for such
tidally-induced spiral structure in a hot massive disk is consistent with their
rarity.Comment: Accepted for publication in Nature (July 19 2012). Includes 15-page
supplemen
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